Tony Medland

Constraint-based approach to investigate the process flexibility of food processing equipment

Over the last decade the UK food processing industry has become increasing competitive. This leads the sector to maintain high numbers of product variations. Although some of these products are stable over long periods, others are short lived or seasonal. The ability to handle both the complexity of process and large variations in product format creates extreme difficulties in ensuring that the existing manufacturing, handling and packaging equipment has the process flexibility to cope. This paper presents an approach for investigating the performance envelopes of machines utilizing a constraint modelling environment. The approach aims to provide the engineer with enhanced understanding of the range of functionality of a given machine and provides the possibility of redesign to process variant product.

Constraint-Aided Product Design

The importance of supporting the early stages of design is widely accepted. In particular, the development of supportive tools and methods for modelling and analysis of evolving design solutions present a difficult challenge. One reason for this is the need to model both the product design and the design knowledge from which the design is created. There are a number of limitations with many existing techniques and an alternative approach that deals with the design constraints themselves is presented. Dealing directly with the constraints affords a more generalised approach that represents the process by which a product is designed. This enables modelling and reasoning about a product from an often abstract and evolving set of requirements. The constraint methodology is an iterative process where the design requirements are elaborated, the constraint rules altered, design ideas generated and tested as functional structures. The incorporation of direct search techniques to solve the constrained problem enables different solutions to be explored and allows the determination of ‘best compromises’ for related constraints. A constraint modelling environment is discussed and two example cases are used to demonstrate the potential of a constraint-aided approach for supporting important issues such as the design of product variants and product families.

A reconfigurable robotic folding system for confectionery industry

Purpose - This paper aims to investigate reconfigurable technology using robotic technology for folding carton in confectionery industry. Design/methodology/approach - Based on the analysis of common motion and manipulation, modules such as robotic fingers and robotic folders are explored and designed. A robotic system is then constructed by arranging those modules for diverse cartons. Findings - A prototyped test rig shows the adaptability of the robotic system. The reconfigurability of the robotic system is realized and verified by experiments and an industrial demonstrator. Practical implications - This research leads to the development of a demonstrator, manufactured and controlled by industries, to further commercial exploitation of this robotic system. It has been applied in a strict industry environment for a chocolate manufacturer. Originality/value - This robotic system applied successfully the theory of reconfigurability by using modularity in packaging systems into confectionery industry.

Case study: Constraint-based improvement of an overwrapping machine

Abstract The paper presents the successful application of a constraint-based modelling to improve the performance of an overwrapping packaging machine. The constraint-based modelling was employed to manipulate the geometry of the individual components and their assemblies until conditions of minimum misalignment forces were achieved. The designs arising from this approach moved the ground points away from their original positions and modified the geometry of the cam follower arms. It also allowed a single camshaft to be used, which enabled a reduction in the number of parts. A prototype of the new design was constructed, installed in the complete machine, and evaluated. All the performance requirements were met.

An approach to investigating the capability of manufacturing equipment for handling food product variation

Commercial pressures in the UK mean food companies must continually reinvent and evolve their products, creating large product families. The ability to handle both the complexity of processes and large variations in product format, leads to considerable difficulties in ensuring that manufacturing and packaging equipment can firstly handle the product, and secondly manufacture it efficiently. This paper presents an approach built on the understanding of the relationships between food product properties and processing parameters. The approach can assist the engineer to redesign the processing equipment from knowing the properties of the product characteristics, and also to reverse engineer the product from the bounds of the process, with the goal of producing a capable and efficient process. The potential for the methodology and its application are summarised for industrial case studies on confectionery carton erection, and the ‘late customisation’ of yoghurt with different fruits.

The Design of Food Processing Systems for Improved Responsiveness and Late Customisation

In designing food manufacturing systems, it is important to have design models to help increase understanding and to predict the behaviour of proposed processes. However, understanding of the properties of the relevant food materials may be limited and the underlying relationships are often highly non-linear. When coupled with models of the manufacturing sy f stem itself, the sensitivities of the various design parameters can be very different. Constraint modelling is a technique that has been used successfully in the design of machine systems. Here it is applied to create an initial model of a yoghurt processing line. The approach is to identify the constraints which bound the application and then to use optimisation techniques to resolve these.

Modelling to Reduce the Configuration Phase Time of Machine Design

The configuration phase for a new machine design is expensive and time consuming for special purpose machine manufacturers. This papers presents a modelling approach that can aid such companies reduce the configuration phase time and its respective costs. The approach is demonstrated with an industrial case study.

Steps Towards Geographically Dispersed Collaborative Student Design Projects

A need exists to teach undergraduate students the skills required for collaborative working in geographically dispersed teams. A program for running collaborative student engineering design projects between the Universities of Bath (United Kingdom) and Canterbury (New Zealand) was implemented in January 2002. This paper presents the approach to collaborative working on this first project. The paper shows that whilst the Universities run on different education programs, and are in different time zones, a path is found for the integration of a collaborative design project within the curriculum of both design courses. The primary forms of communication were email, project web pages and videoconferences. The results of the study provide a basis for further collaborative exchanges between the Universities.Copyright

The study of the interaction of humans with wheelchairs to improve the design

In order to evaluate a wheelchair design it is necessary to look at the capabilities of the user and the chair’s intended purpose. Whilst some chairs are only required to provide infrequent mobility indoors, others need to enable the user to travel great distances out doors over rough terrain. In this respect the chair should be considered in the same manner as any other ‘inclusive’ product (or be useable by all). There is a need to better understand the capabilities of different users and how this affects their ability to use a wheelchair for the express purpose required. A detailed experimental investigation was carried out into the wheelchair propulsion characteristics of people with paraplegia and tetraplegia. In this investigation, subjects’ posture, applied forces, and their strategies in applying forces to the wheel rims were studied. Three distinct postures and corresponding techniques were observed and subsequently modelled in a constraint-modelling environment. Here rules were developed that allowed these differing postures to be applied to a manikin representation and their effect upon the wheelchair mobility evaluated. From this study the needs for these classes of individuals were identified in order to allow the wheelchairs to be evaluated. Where conflicts existed between the chair and the user, different modifications in both chair and posture were proposed and assessed. Where no simple modifications exist such a study can provide the basis for a more radical and improved design.© 2009 ASME

Modelling the evolution of packaging systems for product variation

Manufacturing practices such as mass customization mean producers are often making changes to their product and its respective packaging. Many of these changes arise over short periods due to marketing and customer demands. Some products are stable over long periods whilst others are short lived or seasonal. This paper presents an approach employing the capability of a constraint-based modelling environment to model and simulate variations in machine design configuration to cope with evolving product. The paper continues to explain the product effects, and how understanding product constraint relationships can offer the full understanding of the processing capability for the change product.Copyright